As for a clamp for attaching a pipe such as the filler pipe and the like to a support member such as the vehicle body panel and the like, there is a clamp including a first member attached to the support member, and a second member turnably provided in the first member; preventing the second member from turning by connecting the first member and the second member; and clamping the pipe between the first member and the second member (for example, Patent Document 1).